Asbestos tiles are commonly used as roofing materials of a building constructed with iron bars. However, asbestos tiles are expensive, heavy and fragile, even though they are good heat-insulating and fire-proof materials. It is a common practice that insulating boards are placed under asbestos tiles to ensure that a better insulation is achieved. But such practice is costly. Therefore, some substitutes such as plastic wavy board, metal wavy board, red clay wavy board, etc. have been developed. But they lack adequate insulating property to serve the purpose well and have to be reinforced by means of other insulating materials, such as vinylon board or foaming materials. The application of additional insulating materials like vinylon board and foaming materials is a tedious and costly operation.
The present invention provides a remedy for the situation mentioned above by means of an automated manufacturing process of insulating board, in which waterproof insulating boards produced are automatically coated with foaming agent. As a result, insulating boards can be made in quantity rapidly and economically.